1. Field of the Invention
The invention relates to organopolysiloxanes with Bunte salt groups linked to a silicon atom by way of carbon atoms, the synthesis of these compounds and their use for the surface treatment of inorganic or organic materials. Such compounds are especially useful in the textile industry for the treatment of fibers, yarns, woven and knitted materials or other textile fabrics in order to influence their surface properties, such as, for example, their lubricity, hand, or shrinkage properties, or to impregnate paper or slag wool.
2. Description of the Prior Art
Bunte salts are generally understood to be alkali-S-alkyl or alkali-S-aryl thiosulfates. As used herein, the concept of a Bunte salt group includes the alkali or ammonium salts of the --S.sub.2 O.sub.3.sup..crclbar. group which is linked to a carbon atom.
Bunte salts are hydrolized by aqueous acids with the formation of thiols. In alkaline medium they form the corresponding disulfides as well as other products. This reactivity is utilized for fixing dyes with Bunte salt groups on textile materials. The functional groups of the fibers, such as, the OH group of the celluloses, the amino and thiol groups of wool, or the acid amide groups of synthetic polyamides, act in this reaction as nucleophilic agents. After pretreatment of cellulose with sodium sulfide solution or during the treatment of wool, polycondensation takes place on the substrate with the formation of disulfide bridges. A corresponding dyeing with Bunte salt dyes is therefore washfast. Processes for synthesizing compounds with Bunte salt groups, the properties of these compounds and their use are described in "Angewandte Chemie" 79 (1967), page 520 ff.
The "Textile Research Journal" 62 (1982) page 580 ff. discloses the use of polyethers containing Bunte salt groups, for increasing shrinkproofness.
Organosilicon compounds with Bunte salt groups are described only in the form of the monomeric silanes. The reaction of chloromethyl or .gamma.-chloropropyltrimethylsilanes with aminoethanethiosulfuric acid is known from the "J. Heterocyclic Chemistry" 5 (1968) 115. The reaction between ethylene imine, ammonium thiosulfate and trimethylvinylsilane in which a compound of the formula EQU (CH.sub.3).sub.3 SiCH.sub.2 CH.sub.2 NHCH.sub.2 CH.sub.2 S.sub.2 O.sub.3 NH.sub.4
is formed has also already been described.
However, prior to the present invention, organopolysiloxanes with Bunte salt groups have not been known. Also, it was assumed that their synthesis would create difficulties since the usual synthesis processes for Bunte salts depend on the reaction of reactive compounds with alkali thiosulfate in a polar medium, in which the organopolysiloxanes are insoluble or only slightly soluble. Moreover, it is reported in "Angewandte Chemie" 79, (1967) p. 520 ff, that 1,2-epoxyalkanes generally react with sodium thiosulfate with ring splitting and formation of derivatives of 2-hydroxyethanesulfonic acid.